Biliary dilatation: Differentiation of benign from malignant causes-value of adding conventional MR imaging to MR cholangiopancreatography

PURPOSE: To determine the value of conventional T1 - and T2-weighted images and gadolinium-enhanced dynamic magnetic resonance (MR) images as a Supplement to MR cholangiopancreatographic (MRCP) images in differentiation of benign from malignant causes of biliary dilatation. MATERIALS AND METHODS: MR studies in 62 patients with biliary dilatation with proved causes included conventional T1- and less heavily T2-weighted images, as well as gadolinium-enhanced dynamic images and heavily T2-weighted MRCP images. Two radiologists reviewed MRCP images alone, MRCP images with nonenhanced T1- and T2-weighted MR images, and MRCP images with nonenhanced and gadolinium-enhanced dynamic images. RESULTS: For differentiation of benign from malignant causes of biliary dilatation, the area under the receiver operating characteristic curve (A,) was significantly (P <.05) larger for MRCP images interpreted with T1- and T2-weighted images (0.9547 for reader 1, 0.8404 for reader 2) than for MRCP images alone (0.8144 for reader 1, 0.8122 for reader 2). The addition of gadolinium-enhanced dynamic MR images to MRCP images with nonenhanced T1- and Til-weighted images did ndt significantly increase accuracy (A(z) = 0.9554 for reader 1 and 0.8650 for reader 2), but the level of confidence was increased in 17%-24% of cases. CONCLUSION: Use of nonenhanced T1- and less heavily T2-weighted images with MRCP images significantly improved the diagnostic accuracy of MR examinations of pancreaticobiliary disease.